Environment group Sea Shepherd has failed in its long-running bid to gain charitable tax status in Australia.
In a decision handed down this week, the Administrative Appeals Tribunal ruled that the conservation group was not eligible for deductible gift recipient status because whales, dolphins and other marine wildlife could not be classified as "animals without owners".
The decision means the group will be hampered it in attempts to raise funds in Australia because its supporters will not be able to claim their donations as tax deductions.
It is the latest in a series of applications and appeals by the group for charitable tax status.
Australian director of Sea Shepherd Jeff Hansen said the decision was a major blow to the group, which had a large support base in Australia.
"It is hard to understand how animals in the wild could possibly be excluded from the category of 'animals without owners', but if that is the case the tax laws must be amended immediately to correct such an absurd outcome," Mr Hansen said.
Sea Shepherd is a not-for-profit organisation and has charity status in the United States.
Mr Hansen said Sea Shepherd was involved in many community-based initiatives including beach clean-ups and assisting in whale and dolphin standings in Australia.
"Australia is one of the most passionate countries to defend whales in the world and Sea Shepherd receives the most amazing support from Australians of all backgrounds," he said.